Algebra 1: Common Core (15th Edition)

The order from widest to narrowest is $y=x^2,y=-3x^2,y=5x^2$.
Of the three graphs, $y=x^2$ is the widest, and $y=5x^2$ is the narrowest. So, the order from widest to narrowest is $y=x^2,y=-3x^2,y=5x^2$.